Yet Another Annoying Noise Post (video link)
03-28-2014, 10:21 AM
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Join Date: Jun 2010
Location: Hawaii
Posts: 10
Yet Another Annoying Noise Post (video link)
Hi all,
I've started getting a noise from the rear half of my 2008 GT premium. She has 59k miles on it and I've kept up with all general maintenance like alignments, tire rotations, brakes, oil, etc. I've tried to research and diagnose it myself but no luck figuring it out. Here's the notes I've gathered:
-The noise sounds like a rotational squeak to me. It changes pace with the speed of the car. It reminds me of the noise a bad belt makes.
-The noise only occurs when I accelerate and seemingly only after the car has been moving for a few minutes. Sitting in park or neutral and revving it doesn't cause it (eliminating the possibility of a belt). As soon as I let off the gas it stops. Touches as light as maintaining my current speed on the highway will cause it.
-The noise happens at all speeds (~25 city to ~70 highway). Like I said before it changes pace with the speed of the car.
-Here's a link of the video I took while driving on the highway:
-I replaced the rear brakes pads 2 months ago. The issue did not start until 2 weeks ago though. While replacing them, I used the proper caliper piston tool to twist it in and also properly lubed the ceramic pads as appropriate. The rotors were fine so I reused them. I don't think it could be warped rotors as it doesn't make noise when I coast.
-I jacked up the car and jiggled/tugged the suspect wheel to see if there was any play in it. There was not. This may eliminate the bad wheel bearing theory?
-With the car jacked up (stand under the rear axle), I also pried on all the bushing connections I could find. All bushings in the suspension looked fine.
-Two years ago, one of the stock rear lower control arm bushings went. I replaced both arms with the ford racing gt500 lower control arms. These haven't made any noise/caused any issues ever in those two years. Their bushings look fine.
-While under the car I looked around the drive shaft for anything that might be rubbing against it, all is clear. I also tried to see if there was any rotational play in the drive shaft in park. Thought this might help indicate bad u-joints but there was 0 play in it.
-I don't think it could be a bent axle because there is no noise when I'm coasting at any speed. I haven't had any accidents or ran anything over that could have caused damage to it either.
-I felt the rear differential housing and drive shaft, checking to see if anything was hot (indicating friction) after driving home from work yesterday. I waited long enough that the exhaust pipes were cold but the rear diff housing was warm (maybe because it has fluid in there holding heat). The area on the drive shaft near where the two pieces of it meet was also warm. Not sure if these indicate anything.
-The noise will change in volume or even stop completely when going around turns on the highway/changing lanes/swerving to avoid massive potholes (thanks DC highways).
-The last two points lead me to think it could be a rear differential issue but I haven't opened her up as I don't have the facility to get the car up very high. Does that fluid need to be swapped early on in the car's life? I've had the car from 11,800 to 59,000 miles and I haven't done that yet. The tranny (automatic) fluid should be fine within that mileage too right? I wouldn't think its the tranny since the noise is from the back of the car.
If anyone has any ideas, I'm all ears. I'm more of a do it yourselfer (brakes and alternator earlier this year) but will take her to the shop if I can't definitively figure it out. Please no suggestions of turning the radio up, I appreciate this is a noisey car but it is not normal for mine having all these stock parts. I also am not looking for an excuse to swap out the stock suspension unless that is absolutely the cause. If there's anything I've left out please ask and I'll answer as best I can.
I've started getting a noise from the rear half of my 2008 GT premium. She has 59k miles on it and I've kept up with all general maintenance like alignments, tire rotations, brakes, oil, etc. I've tried to research and diagnose it myself but no luck figuring it out. Here's the notes I've gathered:
-The noise sounds like a rotational squeak to me. It changes pace with the speed of the car. It reminds me of the noise a bad belt makes.
-The noise only occurs when I accelerate and seemingly only after the car has been moving for a few minutes. Sitting in park or neutral and revving it doesn't cause it (eliminating the possibility of a belt). As soon as I let off the gas it stops. Touches as light as maintaining my current speed on the highway will cause it.
-The noise happens at all speeds (~25 city to ~70 highway). Like I said before it changes pace with the speed of the car.
-Here's a link of the video I took while driving on the highway:
-I replaced the rear brakes pads 2 months ago. The issue did not start until 2 weeks ago though. While replacing them, I used the proper caliper piston tool to twist it in and also properly lubed the ceramic pads as appropriate. The rotors were fine so I reused them. I don't think it could be warped rotors as it doesn't make noise when I coast.
-I jacked up the car and jiggled/tugged the suspect wheel to see if there was any play in it. There was not. This may eliminate the bad wheel bearing theory?
-With the car jacked up (stand under the rear axle), I also pried on all the bushing connections I could find. All bushings in the suspension looked fine.
-Two years ago, one of the stock rear lower control arm bushings went. I replaced both arms with the ford racing gt500 lower control arms. These haven't made any noise/caused any issues ever in those two years. Their bushings look fine.
-While under the car I looked around the drive shaft for anything that might be rubbing against it, all is clear. I also tried to see if there was any rotational play in the drive shaft in park. Thought this might help indicate bad u-joints but there was 0 play in it.
-I don't think it could be a bent axle because there is no noise when I'm coasting at any speed. I haven't had any accidents or ran anything over that could have caused damage to it either.
-I felt the rear differential housing and drive shaft, checking to see if anything was hot (indicating friction) after driving home from work yesterday. I waited long enough that the exhaust pipes were cold but the rear diff housing was warm (maybe because it has fluid in there holding heat). The area on the drive shaft near where the two pieces of it meet was also warm. Not sure if these indicate anything.
-The noise will change in volume or even stop completely when going around turns on the highway/changing lanes/swerving to avoid massive potholes (thanks DC highways).
-The last two points lead me to think it could be a rear differential issue but I haven't opened her up as I don't have the facility to get the car up very high. Does that fluid need to be swapped early on in the car's life? I've had the car from 11,800 to 59,000 miles and I haven't done that yet. The tranny (automatic) fluid should be fine within that mileage too right? I wouldn't think its the tranny since the noise is from the back of the car.
If anyone has any ideas, I'm all ears. I'm more of a do it yourselfer (brakes and alternator earlier this year) but will take her to the shop if I can't definitively figure it out. Please no suggestions of turning the radio up, I appreciate this is a noisey car but it is not normal for mine having all these stock parts. I also am not looking for an excuse to swap out the stock suspension unless that is absolutely the cause. If there's anything I've left out please ask and I'll answer as best I can.
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